Electrical distribution system



y .1942. K. SCHMITT 2,283,231

ELECTRICAL DISTRIBUTION SYSTEM Filed Dec. 8, 1939 2 Sheets-Sheet 1 i l: 1 I l Z121 Joy/W7 B I Attorbey lnveniol' May'19, 1942. K. SCHMITT I ELECTRICAL DISTRIBUTION SYSTEM Filed Dec. 8, 1939 2 Sheets-Sheet 2 In venton- MPLJcw/ rr Patented May 19, 1942 ELECTRICAL DISTRIBUTION SYSTEM Karl Schmitt, Stuttgart-Degerloch, Germany, as-

h. c. F. Porsche K.-G., Stuttgart-Zuffenhausen, Germany, a company signor to Dr. ing.

of Germany Application December 8, 1939, Serial No. 308,249

In Germany November 25, 1938 12 Claims.

This invention relates to an electrical distribution system, and more particularly to one for supplying current to a plurality of loads on an automobile or other vehicles. The present application is a continuation in part of my prior copending application Serial No. 280,529, filed June 22nd, 1939.

An object of this invention is to provide an improved electrical distribution system for vehicles.

Another object of this invention is to provide an improved safety cut-out system, responsive after a predetermined time to a short circuit in a vehicle electrical distribution system.

A further object of this invention is the provision of improved delayed-action safety cut-out and transfer switches. I

A still further object of this invention is the provision of an improved safety lighting system for vehicles.

A more specific object of this invention is to provide a lighting system for vehicles, wherein a main light source is automatically cut out after a predetermined time upon the occurrence of an overload or a short circuit in the electrical dis.- tribution system, and simultaneously therewith an auxiliary light source is energized.

Other objects will become apparent from the following description taken in connection with the attached drawings showing several illustrative embodiments of the invention, and wherein:

Fig. 1 is a circuit diagram of a preferred embodiment of the improved electrical distribution system arranged in accordance with this invention;

Fig. 2 is a detailed view drawn to' a larger scale of the improved safety cut-out and transfer switch embodied in the system illustrated in Fig. 1;

Fig. 3 shows a modified form of safety cut-out and transfer switch which may be substituted for that illustrated in Fig. 1; and

Fig. 4 illustrates another modified safety cutout and transfer switch which may be used in the system. i

As shown in Fig. 1, a suitable source of power, such as a battery I is connected through the starting switch 2 to the usual ignition system of a vehicle engine, generally indicated at 3, and to the starter-generator 4. Power to the main loads is supplied from the battery I through the conductor I05 through the intermediation of an automatic switch I06, to be described in more detail hereinafter. In the illustrated position of the switch, current will flow from the energized conductor I05 through the actuating coil I3I, the

contact bridge 8, bridging contacts 9 and I0, and then to the conductor I I I. Upon closure of the proper switches, diagrammatically indicated, current will fiow from the conductor III to the horn I2, the instrument panel light I3, the lighter I4 or any other similar load such as clock, fan, radio, or the like. Upon closure of the switch I5, power is also supplied to the headlight circuit of the vehicle, consisting in the illustrated case of a reversing switch I6 for supplying power either to the main light source Il or an auxiliary light source I8. The light sources I1 and I8 may be entirely separate lamps, or may consist of two lamps positioned in one headlight structure or may be separate filaments for single lamps, all of which is well known in the art. Reversing switch I6 is used to connect either one or the other of the light sources to the main lighting and power circuits for the vehicle, depending upon the choice of the driver of the vehicle. The manner of operating the switch I6 is unimportant, this switch, for example, being hand-operated or foot-operated, as is also well known in the art. 2

In addition to contact members 8, 9 and III for the main loads of the electrical distribution system, the automatic switch is also supplied with a contact bridge 20, which is adapted to bridge an additional pair of contacts 2| and 23. It will be seen that if this circuit is closed, power will flow from the energized conductor I05 and the conductor 22 through contact bridge 20, contacts 2I and 23 and conductor I24 to the reversing switch I6 through which power may be supplied to light sources II or I8.

Pivoted upon a relatively stationary bracket 25 of the switch member I06 is a latch 26 which is adapted to hold the contacting bridge 8 in either one of two raised positions. The latch 26 is also provided with an arm 21 acted upon by a spring 28 to urge the latch 26 toward its retaining position. A wire or cable 29 is provided for releasing the latch 26 in opposition to the force of the spring 28. The cable 29 may extend through the instrument board of the vehicle, generally indicated at 30, so that it can be easily and quickly actuated by the driver of the vehicle.

The aforedescribed system is substantially identical with that contained in my said copending application Serial No. 280,529. In the present case, however, the core I0I of the switch I06 in addition to its actuating coil I3I, is also provided with a short-circuited winding I33. The winding I33 may be short circuited through a separate resistance I32, or may be formed of high resistance wire itself, so that an inserted resistance is not necessary. In the form of the switch shown in Fig. 1, and more particularly in Fig. 2, it will be seen that the windings I3I and I33 are inductively coupled so that the current produced in the winding I33 through transformer action upon a change in current through the winding I3I, such as would occur during a short circuit or temporary overload, will oppose the force exerted by the current coil I3I for a short period of time, and thereby delay the pulling effect of the actuating coil I3I. As a result, the switch I06 will not work unless there is a true permanent fault in the line, as contrasted with the system described in my prior copending application in which the switch would work even upon temporary overload, such as caused by connecting any additional loads. The improved system, therefore, limits its action to cases of necessity where a true fault in the system is present, but avoids all unnecessary action due to mere temporary overload.

In order to show the operation of the aforedescribed system, let it be assumed that the necessary switches are closed to supply power to the various loads I2, I3 and I4, while the switch I5 and reverse switch I6 are closed to place the main light source I1 in the main power circuit. 'The automatic switch I06 will under normal conditions remain in the position illustrated due to the force of the spring I9, which is sufficient to overcome the opposing force of the current coil during the normal flow of load current. If, now, an overload due to any reason I,

whatsoever does occur in one of the main load circuits, the actuating coil I3I of the switch I06 will tend to raise the core I07 and with it the contact bridges 8 and 20, to break the circuit through contacts 9 and I0 and to close the auxiliary light circuit through contacts 2I and 23. This action of the coil I3I will be opposed for a short period of time, however, by the force produced by the induced currents in short circuited coil I33. If the increase in current is due to a mere temporary overload such, for example, by switching in the lighter I4 when the other loads are already in the circuit, it is not desirable that the transfer from one lighting circuit to the other be made, and such transfer will be sufiiciently opposed by the coil I33. If, however, the increased current in coil I3I results from a fault, such as a permanent short circuit, after the short period of time the effect of the coil I33 will disappear and the coil I3I will carry through the switching operation. Thus, the circuit to the main light source I! will be broken but at the same time the auxiliary light source I8 will be energized, so that the driver of the vehicle will still have suflicient illumination despite the presence of a fault in the main lighting system. Through the reversing switch I6, the relative position of the main and auxiliary light sources I! and I8 may be reversed.

After the short-circuit has been removed, the

system may be restored to its original condition by releasing the latch 26 through actuation of the wire or cable 29. The switch I66, however, also provides an easy manner for testing the circuits and a quick ascertaining of the short circuit fault. If the latch 26 is released only to such an extent as to hold the contact bridge 8 in its intermediate'position, both the main and auxiliary circuits will be de-energized. If, while the switch is in this position, the various loads are disconnected and then individuallyreconported in the stationary member.

nected, the faulty device is soon discovered. Let it be assumed that the short-circuit is in the lighter I4. If the horn switch is connected and the latch released so that the contact bridge 8 will engage contacts 9 and I0 the switch will remain closed. If the dash-panel light switch I3 is closed still nothing will happen. However, when the lighter switch is closed, the automatic switch I00 will operate after a predetermined interval of time, indicating that the fault lies in the lighter circuit. Upon the occurrence of a fault, the switch acts not only to automatically disconnect the faulty circuit, but the high current flowing through the coil I3I will produce a buzzer effect thus, in addition, giving an aural indication of the fault. It will be thus seen that the novel system arranged in accordance with this invention not only serves as a safety system, but as a means for readily testing circuits, without blowing and consuming a large number of fuses.

While not indicated as such, it is to be understood that each light source II and I8 may consist of a pair of lights on opposite sides of the vehicle in accordance with the usual arrangement upon automobiles.

Instead of a short-circuited coil, it is to be understood that the switch I06 may be provided with other types of time delay devices, such as an oil or air dash-pot.

Another form of switch which may be used in connection with the safety circuit illustrated in Fig. 1, has been illustrated in Fig. 3. In this case, the conductor coming from the source of power has been indicated as 205, while the switch itself has been designated as 206. The conductor 205 is connected to a stationary member 209 and electrically to a bimetallic strip 234 sup- The bimetallic strip is preferably supplied with suitable contacting plates substantially intermediate its ends, which are adapted to cooperate with contacts 2I0 and 22I to respectively complete the circuit to the main load and main headlights through conductor 2H and to the auxiliary light source through conductor 224. The bimetallic strip 234 is urged in the direction of contact 22I by means of spring 2I9, but is held against the force of the spring 2I9, in contact with contact 2I0 by the latch member 226. If the switch is assumed to be in the position shown in Fig. 3, normal current will flow from energized conductor 205, through the bimetallic strip 234, contact 2I0. and conductor 2II to the main load. The normal flow of current through the bimetallic member 234 will not be suflicient to cause appreciable movement thereof. If, however, an overload occurs and continues for an appreciable length of .time, as, for example, upon the occurrence of a short-circuit fault, the bimetallic member 234 will bend to such a degree that, with the help of the spring 2I9 it will become disengaged from the notch I and will finally come to the position shown in dotted lines, that is, into the notch III and in contact with the contact 22I. It will accordingly be seen, that if the switch illustrated in Fig. 3 is substituted for that shown in Fig. 2, the control of the lighting circuit will be substantially the same. After the short-circuit has been removed, the bimetallic element 234 may be restored to its original position by means of a suitable push rod 229. Suitable means such as a spring 228 may be used to maintain engagement between the bimetallic element 234 and the latch 226.

A third type-of automatic safety cut-out and transfer switch, suitable for the aforedescribed system, is illustrated in Fig. 4. The switch 306 is there connected through the energized conductor 335, while conductors 3H and 324 respectively lead to the main loads and mainheadlight source, and to the auxiliary headlight source. In the switch 336, a spring switch arm 336 is normally held in place by a contacting fusible wire 335, and the electrical circuit is accordingly normally established from the conductor 395, the contact 389, spring switch arm 336, fusible wire 335, contact 3), conductor 3 and then to the main loads and headlight source. Upon the occurrence of a short-circuit or a long overload, the fusible wire 335 will melt and release the spring arm 336 so that it-will come in contact with an appropriately positioned contacting plate 32! connected to the conductor 324. The circuit now established will accordingly come from the energized conductor 335, contact 309,

switch arm 333, contacting plate 32!, conductor 324 and then to the auxiliary headlight source. It will thus be seen that the effect of the switch illustrated in Fig. 4 in the system illustrated in Fig. 1 will be substantially the same as that of the switches respectively shown in Figs. 2 and 3. The switch illustrated in Fig. 4, however, may be advantageously formed as a replaceable unit, the spring switch arm 336 and the fusible wire 335 holding it being mounted upon a plate 331 which can be slipped between stationary contacts 333 and am. After the fault in the circuit has been discovered and corrected, the replaceable unit can be removed and a new one inserted between the stationary contacts, ready to act in case of an additional fault. Accordingly, the type of structure illustrated in Fig. 4,

while similar to the usual circuit-protectin fuses, possesses the further advantage of acting as a transfer switch so that at least temporarily, the vehicle will still be provided with sumcient light, despite failure of the main lighting circuit.

While I have herein shown and described only certain embodiments of certain features of my present invention, it is to be understood that they are to be regarded merely as illustrative, and that I do not intend to limit myself thereto except as may be required by the following claims.

I claim:

1. In an electrical distribution system, a source of power, one or more main loads, an auxiliary load, and means for connecting said main load to said source of power, said means including further repeatedly usable permanent means responsive to a predetermined current flow to said main load for a predetermined time for disconnecting said main load from said source of power and substantially simultaneously connecting said auxiliary load to said source of power.

2. In an electrical distribution system, a source of power, one or more main loads, a switch having an actuating coil, contacts serially connected intermediate said source of power and said loads, means for normally holding said contacts closed in opposition to said actuating coil, an auxiliary load, and further normally open contacts on said switch intermediate said source of power and said auxiliary load, said switch including means responsive to a predetermined flow of current through said actuating coil and operable after a predetermined period of time for opening said normally closed contacts to disconnect said main load, andclosing said normally open contacts to connect said auxiliary load to the source of power.

3. In an electrical distribution system for vehicles, a source of power, one or more main loads, one of which is a first headlight source, a second headlight source, switching means normally connecting said source of power with said main load and responsive to a flow of current above a predetermined maximum for disconnecting said main load and connecting said second headlight source to said source of power, and repeatedly usable permanent means for delaying the response of said switching means to the said flow of current.

4. In an electrical distribution system, a source of power, one or more main loads, an auxiliary load, and switching means for connecting said source of power to one or the other of said loads, including a core, a pair of contacting bridges carried by said core, a pair of first contacts normally bridged by one of said bridges, an actuating coil for said core connected at one end to said source of power and at the other end to one of said first pair of contacts, a conductor connecting the other of said first pair of contacts tosaid main load, a short-circuited coil surrounding said core to delay movement of said switch in response to current fiow through said first coil, a second pair of contacts adapted to be bridged by the other bridge upon movement of said switch by said actuating coil, a conductor connecting one of said second pair of contacts to said source of power, and a conductor connecting the other of said second pair of contacts to said auxiliary load.

5. The combination according to claim 4, in combination with releasable means for retaining said switch in its actuated position after movement thereof by said actuating coil.

6. In an electrical distribution system, a source of power, one or more main loads, an auxiliary load, switching means for normally connecting said source of power to said main load, said switching means including repeatedly usable permanent thermal means responsive to a predetermined current flow to said main loads for a predetermined time for breaking the circuit to said main loads and substantially simultaneously connecting said auxiliary load to the source of power.

'7. In an electrical distribution system, a source of power, one or more main loads, an auxiliary load, a bimetallic thermal element having a pair of contacting faces and connected at one end to said source of power, a first stationary contact connected to said main load and normally in contact with one of said contacting faces, and another stationary contact connected to the auxiliary load and adapted to be contacted by the other contacting face after heating of said thermal element by the current to said main loads for a predetermined time and to a predetermined degree.

8. In an electrical distribution system, a source of power, one or more main loads, an auxiliary load, a releasable spring switch arm, a fusible wire restraining movement of said switch arm and electrically serially interconnecting said arm with said source of power and said main loads, and a contact connected to said auxiliary load and mounted for engagement by said switch arm upon release of the latter by melting of said restraining fusible wire due to predetermined excess current flow therethrough, for connecting said source of power to said auxiliary load.

9. The combination according to claim 8, in combination with a pair of additional stationary contacts connected to said source of power and said main load, and in which said switch arm and said fusible wire are formed as a replaceable unit mounted between said additional stationary contacts.

10. A commutating device having a common terminal and a pair of terminals alternatively connectible to said common terminal, a switching member for connecting said common terminal to said alternatively connectible terminal, means for biasing said switch member to connect said common terminal with one of said pair of terminals, current responsive means energizable upon connection of said common terminals with the said one of said pair of terminals for actuating said switching members to connect said common terminal with the other of said pair of terminals, and time delay means for delaying movement of said switch member by said current responsive means.

11. The combination according to claim 7, in

combination with an arm having a pair of notches, one of said notches being adapted to engage said bimetallic thermal element to hold it against said first stationary contact until said thermal element is heated and deformed to a predetermined degree, whereupon said thermal element becomes disengaged from the one notch and is held in place by the other notch, and manual means for returning said thermal element from said other notch to said one notch.

12. An electro-magnetic switch having a coil adapted to be electrically energized, a movable core actuated by said coil, a pair of contact bridges connected for movement by said core, contacts cooperating with each contact bridge, said core being movable between extreme positions for alternatively producing engagement between each of said bridges and its cooperating contacts, means opposed to the action of said coil for urging retention of the core in one extreme position, and means for holding said core in its other extreme position or in a position intermediate said extreme positions.

KARL SCHMITT. 

